Method of optimizing system efficiency for battery powered electric motors

1. A method of controlling an electric motor, the method comprising:

determining a pulsed system efficiency for an electric motor at least partially based on operating conditions of a battery system providing energy to the electric motor to deliver a requested torque; and

operating the electric motor in a pulsed mode when the pulsed system efficiency is greater than a continuous system efficiency.

2. The method of claim 1 , wherein determining the pulsed system efficiency includes the pulsed system efficiency comprising a product of a pulsed motor efficiency and a pulsed battery system efficiency.

3. The method of claim 1 , wherein determining the pulsed system efficiency includes determining a pulsed battery efficiency at least partially based on a dissipated heat loss of the battery system.

4. The method of claim 1 , wherein determining the pulsed system efficiency at least partially based on the operating conditions of the battery system comprises the operating conditions of the battery system including a battery temperature, a pulsing current, a battery terminal voltage, or a battery internal resistance.

5. The method of claim 1 , further comprising:

calculating the continuous system efficiency for delivering the requested torque from the electric motor in a continuous mode; and

operating the electric motor in the continuous mode when the continuous system efficiency is greater than the pulsed system efficiency.

6. The method of claim 1 , wherein determining the pulsed system efficiency includes determining a pulsed motor efficiency of the electric motor at least partially based on operating conditions of the electric motor.

7. The method of claim 6 , wherein determining the pulsed motor efficiency comprises the operating conditions of the electric motor including a motor speed, a motor torque, a vehicle speed, or a motor temperature.

8. The method of claim 1 , further comprising generating a pulse waveform for delivering the requested torque from the electric motor in the pulsed mode.

9. The method of claim 8 , wherein generating the pulse waveform includes pulsing the electric motor at a pulse torque greater than the requested torque to deliver the requested torque.

10. The method of claim 8 , wherein generating the pulse waveform includes regenerating energy between pulses of the electric motor.

11. A non-transitory computer-readable storage medium having instructions stored thereon that, when executed by a controller, cause the controller to:

determine a pulsed system efficiency for an electric motor at least partially based on operating conditions of a battery system that is configured to provide energy to an electric motor to deliver a requested torque; and

operate the electric motor in a pulsed mode when the pulsed system efficiency is greater than a continuous system efficiency.

12. The non-transitory computer-readable storage medium of claim 11 , wherein the controller determines the pulsed system efficiency by determining a pulsed battery efficiency at least partially based on a dissipated heat loss of the battery system.

13. The non-transitory computer-readable storage medium of claim 11 , wherein the controller determines the pulsed system efficiency at least partially on the operating conditions of a battery system comprises the operating conditions of the battery system including a battery temperature, a pulsing current, battery terminal voltage, or battery internal resistance.

14. The non-transitory computer-readable storage medium of claim 11 , wherein the controller calculates the pulsed system efficiency based at least partially on a pulsed motor efficiency.

15. The non-transitory computer-readable storage medium of claim 11 , wherein the controller is further caused to:

calculate the continuous system efficiency for delivering the requested torque from the electric motor in a continuous mode; and

operate the electric motor in the continuous mode when the continuous system efficiency is greater than the pulsed system efficiency.

16. A controller for operating an electric motor to rotate a driven component, the controller comprising:

a processor; and

a memory including a program to cause the processor to:

determine a pulsed system efficiency for an electric motor at least partially based on operating conditions of a battery system that is configured to provide energy to an electric motor to deliver a requested torque; and

operate the electric motor in a pulsed mode when the pulsed system efficiency is greater than a continuous system efficiency.

17. The controller according to claim 16 , wherein determining the pulsed system efficiency includes determining a pulsed battery efficiency at least partially based on a dissipated heat loss of the battery system.

18. The controller according to claim 16 , wherein determining the pulsed system efficiency at least partially on the operating conditions of a battery system comprises the operating conditions of the battery system including a battery temperature, a pulsing current, battery terminal voltage, or battery internal resistance.

19. The controller according to claim 16 , wherein calculating the pulsed system efficiency is based at least partially on a pulsed motor efficiency.

20. The controller according to claim 16 , wherein the program further causes the processor to:

calculate the continuous system efficiency for delivering the requested torque from the electric motor in a continuous mode; and

operate the electric motor in the continuous mode when the continuous system efficiency is greater than the pulsed system efficiency.